In this paper, we compare performance of several dimension reduction techniques, namely LSI, random projections and FastMap. The qualitative comparison is based on rank lists and evaluated on a subset of TREC 5 collection and corresponding TREC 8 ad-hoc queries. Moreover, projection times and intrinsic dimensionality were measured to present a common baseline for methods’ usability.

This paper briefly describes the Qatar Computing Research Institute (QCRI) participation in the TREC 2011 Microblog track. The focus of our TREC submissions was on using a generative graphic model to perform query expansion. We trained a model that attempted to predict appropriate hashtags to expand tweets as well as queries. In essence, we used hashtags to represent latent topics in tweets.

The TREC Web Track explores and evaluates Web retrieval technology over large collections of Web data. In its current incarnation, the Web Track has been active for two years. For TREC 2010, the track includes three tasks: 1) an adhoc retrieval task, 2) a diversity task, and 3) a spam task. As we did for TREC 2009, we based our experiments on the billion-page ClueWeb09 data set created by the L...

Thymic function is critical for immune reconstitution after hematopoietic stem cell transplantation (HSCT). We evaluated recipient thymic function before HSCT by quantifying T-cell receptor excision circles (TRECs) in pretransplantation peripheral blood lymphocytes from 102 patients who received HSCs from an HLA-identical sibling for malignant (n = 87) or nonmalignant diseases (n = 15). Median ...

Efficient and low-cost systems are needed to harvest the tremendous amount of energy stored in low-grade heat sources (<100 °C). Thermally regenerative electrochemical cycle (TREC) is an attractive approach which uses the temperature dependence of electrochemical cell voltage to construct a thermodynamic cycle for direct heat-to-electricity conversion. By varying temperature, an electrochemical...

This paper is concerned with expert search, a search task where the user types a query representing a topic and the search system returns a ranked list of people who are considered experts on the topic. The system does this using the evidence existing in a document collection. We proposed a model for performing the task in our TREC 2005 submission, referred to as two-stage model. Since that, a ...

This report describes DIMACS work on the text categorization task of the TREC 2005 Genomics track. Our approach to this task was similar to the triage subtask studied in the TREC 2004 Genomics track. We applied Bayesian logistic regression and achieved good effectiveness on all categories. 1. TEXT CATEGORIZATION TASK The Mouse Genome Informatics (MGI) project of the Jackson Laboratory provides ...

It is generally believed that homeostatic responses regulate T-cell recovery after peripheral stem cell transplantation (PSCT). We studied in detail immune recovery in relation to T-cell depletion and clinical events in a group of adult patients who underwent PSCT because of hematologic malignancies. Initially, significantly increased proportions of dividing naive, memory, and effector CD4(+) a...

Research in Information Retrieval has traditionally focused on serving the best results for a single query. In practice however users often enter queries in sessions of reformulations. The Sessions Track at TREC 2010 implements an initial experiment to evaluate the effectiveness of retrieval systems over single query reformulations.

Research in Information Retrieval has traditionally focused on serving the best results for a single query. In practice however users often enter queries in sessions of reformulations. The Sessions Track at TREC 2010 implements an initial experiment to evaluate the effectiveness of retrieval systems over single query reformulations.